World Down Syndrome Day (WDSD) is an annual March 21 celebration and global awareness day officially observed by the United Nations since 2012. March 21 (3/21) was selected to signify the uniqueness of the triplication (trisomy) of the 21st chromosome which causes Down syndrome. The theme for 2022 WDSD is inclusion.

World Down Syndrome Day is marked each year on March 21, beginning in 2006. The 21st day of March was selected to signify the uniqueness of the triplication of the 21st chromosome which causes Down syndrome. Every year on March 21, World Down Syndrome Day is observed to create awareness about Down syndrome.

Dhanaidaha Haque Autistic & Buddhi Protibondhi Biddaloy has been celebrating this day with due dignity since its establishment. School has been observing this day through rallies and other activities.